You know That Guy? The guy who wears cologne like a marinade? You can smell him a city block away? Can't stand to be in the same bus or subway car as him? Yeah. That's how airborne disease works, except you can't smell it. The same distance you can be away from That Guy and not smell his cologne is the same distance you can be safely unmasked near other people. If you're close enough to smell That Guy's cologne at all, you're close enough to need a mask. COVID Threads